Abu Dawud Book 2, Hadith Number 1343.

Chapter : On the number of rakahs of the prayer at night.

Narated By Zurarah b. Awfa : ‘Aisha was asked about the prayer of the Apostle of Allah (PBUH). She said: He used to lead the people in the night prayer and return to his family and pray four rak’ahs and go to his bed. The narrator then transmitted the tradition in full. This version does not mention the words: “During them (rak’ahs) he equated all the recitation of the Qur’an, bowing and recitation.” This also does not mention about the salutation: “Till he almost awakened us.”